Semiconductor device and manufacturing method thereof

ABSTRACT

A semiconductor device is provided, which comprises a first electrode, crystalline semiconductor particles, a semiconductor layer, and a second electrode. The crystalline semiconductor particles of which adjacent particles are fusion-bonded, the crystalline semiconductor particles have a first conductivity type, and the semiconductor layer has a second conductivity type which is different from the first conductivity type.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a photoelectric conversion device thatconverts light energy into electrical energy, and particularly relatesto a photoelectric conversion device using crystalline semiconductorparticles and a manufacturing method thereof.

2. Description of the Related Art

Solar cells with high conversion efficiency using monocrystalline orpolycrystalline silicon wafers have been put to practical use. Inparticular, in response to global environmental issues in recent years,the market for residential photovoltaic systems and the like hasexpanded.

These solar cells are manufactured by being cut out of large siliconingots. However, it takes a long time to manufacture large siliconingots, which means productivity is low, and since supply of rawmaterial of silicon itself is limited, the supply of silicon ingots isinsufficient and cannot respond to the expansion of the market for solarcells.

Although amorphous silicon solar cells are known as solar cells that donot use large silicon ingots, conversion efficiency after stabilizationremains low, and are unsuited to function as electrical power.

As a photoelectric conversion device that does not need a large siliconingot, a photoelectric conversion device using silicon crystallineparticles has been suggested (for examples, refer to Patent Document 1:Japanese Patent No. 2641800 and Patent Document 2: Japanese PublishedPatent Application No. 2005-159167). This photoelectric conversiondevice is based on a structure of providing and fixing a large number ofone-conductivity type semiconductor particles over a substrate providedwith a lower electrode or a substrate that becomes a lower electrode,and then forming a semiconductor layer that has an opposite conductivitytype to the one-conductivity type, so that a p-n junction is formed.

SUMMARY OF THE INVENTION

However, with the conventional photoelectric conversion device usingsemiconductor particles, a photoelectric conversion layer is formed bydispersing individual semiconductor particles; consequently, thereexists a problem that an area which contributes to photoelectricconversion substantively is reduced. That is, compared to theconventional solar cells manufactured from silicon ingots, there is aproblem that conversion efficiency per unit area is reduced.

In view of the foregoing problem, an object of the present invention isto provide a photoelectric conversion device with high conversionefficiency and favorable productivity, and a manufacturing methodthereof.

A photoelectric conversion device of the present invention is aphotoelectric conversion device using one-conductivity type or intrinsiccrystalline semiconductor particles of which adjacent particles arefusion-bonded to each other. A junction in this photoelectric conversionlayer is formed of the one-conductivity type or intrinsic crystallinesemiconductor particles of which adjacent particles are fusion-bonded toeach other, and a semiconductor layer that has an opposite conductivetype to the one-conductivity type. The one-conductivity type orintrinsic crystalline semiconductor particles of which adjacentparticles are fusion-bonded to each other may be stacked to form acrystalline semiconductor particle layer.

By using the one-conductivity type or intrinsic crystallinesemiconductor particles of which adjacent particles are fusion-bonded toeach other, it can be made so that movement of photogenerated carriersin a light-accepting flat surface direction (lateral direction) is notinhibited. Also, by leaving a shape of the crystalline semiconductorparticles as is, an acceptance surface of the photoelectric conversiondevice can be made to be irregular.

According to the present invention, by using the one-conductivity typeor intrinsic crystalline semiconductor particles of which adjacentparticles are fusion-bonded to each other, movement of thephotogenerated carriers in the light-accepting flat surface direction(lateral direction) is not inhibited, and efficiency of carriercollection is improved; consequently, photoelectric conversionefficiency can be improved. Further, since a p-n junction is formedwhile retaining the shape of the crystalline semiconductor particles,area of light acceptance that substantively contributes to photoelectricconversion is increased, which contributes to improving conversionefficiency.

The photoelectric conversion device of the present invention can be usedas a solar cell for electrical power that is installed outdoors. In thatcase, since a large-area photoelectric conversion device can bemanufactured without using a large silicon ingot, raw material ofsilicon is not wastefully consumed. Also, in addition to using forelectrical power, the photoelectric conversion device can be used as alow electric power source for consumer appliances such as a calculator,a clock, and the like.

BRIEF DESCRIPTION OF DRAWINGS

In the following drawings:

FIG. 1 describes a manufacturing step of a photoelectric conversiondevice of Embodiment Mode 1;

FIG. 2 describes a manufacturing step of a photoelectric conversiondevice of Embodiment Mode 1;

FIG. 3 describes a manufacturing step of a photoelectric conversiondevice of Embodiment Mode 1;

FIG. 4 describes a manufacturing step of a photoelectric conversiondevice of Embodiment Mode 1;

FIG. 5 describes a manufacturing step of a photoelectric conversiondevice of Embodiment Mode 2;

FIG. 6 describes a manufacturing step of a photoelectric conversiondevice of Embodiment Mode 2;

FIG. 7 describes a manufacturing step of a photoelectric conversiondevice of Embodiment Mode 2;

FIG. 8 describes a manufacturing step of a photoelectric conversiondevice of Embodiment Mode 2;

FIG. 9 shows a structure of an aerosol laser ablation for generatingcrystalline semiconductor particles;

FIG. 10 shows a structure of a vapor growth apparatus for generatingcrystalline semiconductor particles; and

FIG. 11 describes a manufacturing step of a photoelectric conversiondevice of Embodiment Mode 3.

DETAILED DESCRIPTION OF THE INVENTION Embodiment Mode

Embodiment modes of the present invention will hereinafter be describedin detail based on the accompanying drawings. However, the presentinvention is not limited to the description below, and it is easilyunderstood by those skilled in the art that modes and details hereindisclosed can be modified in various ways without departing from thespirit and the scope of the present invention. Therefore, the presentinvention should not be interpreted as being limited to the descriptionof the embodiment modes to be given below. Note that in the structure ofthe present invention described hereinafter, reference numerals denotingthe same portions are used in common in the drawings, and repeateddescription thereof may be omitted.

Embodiment Mode 1

FIGS. 1 to 4 describe manufacturing steps of a photoelectric conversiondevice of this embodiment mode. In this embodiment mode, an example ofmanufacturing a photoelectric conversion device using crystallinesemiconductor particles each with a grain diameter of severalmicrometers to several tens of micrometers (1 micrometer to 99micrometers), in order to improve conversion efficiency, is described.

In FIG. 1, a first electrode 102 is formed over a substrate 101. It isacceptable as long as the substrate 101 can resist a temperature ofabout 500° C., and alumino borosilicate glass, barium borosilicateglass, or the like, which is called a non-alkali glass substrate; aquartz substrate; or a metal substrate such as a stainless steelsubstrate can be used. For the first electrode 102, a low melting metalsuch as aluminum (Al), indium (In), tin (Sn), or zinc (Zn) is preferablyused. This is so that the crystalline semiconductor particles arefusion-bonded to each other in a later step. For example, tin (Sn) has amelting point of 232° C., and is also a tetratomic metal; therefore, itis preferable since it does not change a conductivity type of thecrystalline semiconductor particles, in a fusion-bonding step.

In FIG. 2, p-type crystalline semiconductor particles 103 each with agrain diameter of 5 μm to 30 μm are densely dispersed over the firstelectrode 102 formed of a low melting metal. Size of the particles maybe appropriately selected taking into consideration the lifetime and alight absorption coefficient of a crystal. The crystalline semiconductorparticles 103 are of silicon, germanium, silicon-germanium, or the like.In order to make the crystalline semiconductor particles 103 to bep-type, boron (B), aluminum (Al), or gallium (Ga) may be added for apurpose of controlling a valence electron. The crystalline semiconductorparticles 103 can be formed by a vapor growth method, an atomizingmethod, a direct current plasma method, a melt drop method, or the like.It is preferable that grain diameters of the crystalline semiconductorparticles are uniform.

FIG. 3 shows a step of carrying out a heat treatment. The firstelectrode 102 is heated, and the crystalline semiconductor particles 103are fixed thereto. That is, the first electrode 102 is heated to itsmelting point temperature, or a temperature at which liquefactionoccurs, and the crystalline semiconductor particles 103 are fixed to thefirst electrode 102.

Further, a step is carried out in which a treatment of fusion-bondingthe crystalline semiconductor particles 103 to each other, is carriedout. By fusion-bonding the crystalline semiconductor particles 103 toeach other, an area for absorbing light increases within a substratesurface. Crystalline semiconductor particles 104 that are fusion-bondedallow diffusion of photogenerated carriers to an adjacent crystallinesemiconductor particle, and therefore efficiency of carrier collectionis improved. That is, since the area substantively contributing tophotoelectric conversion increases by this step, conversion efficiencycan be improved.

The treatment of fusion-bonding the crystalline semiconductor particles103 to each other may be of heating to, for example, 1412° C. which isthe melting point of silicon, but the treatment is preferably laser beamirradiation. As a laser light source, a continuous wave (CW) laser oflaser diode (LD) excitation (YVO₄, second harmonic (wavelength 532 nm))can be used. Although it is not particularly necessary that the laser islimited to the second harmonic, the second harmonic is better than aharmonic of a higher order in terms of energy efficiency. When thecrystalline semiconductor particles 103 are irradiated with the CWlaser, energy is given continuously to a semiconductor film;consequently, a surface of the crystalline semiconductor particles 103can be made to be in a fusion state for at least a certain period oftime. Consequently, adjacent crystalline semiconductor particles 103 canbe fusion-bonded to each other. Also, a reason for using a solid laseris because compared to a gas laser or the like, the solid laser has highstability of output, and stable treatment is expected. Note that otherthan the CW laser, a pulsed laser with a repetition frequency of 10 MHzor more can also be used.

If a pulse interval of the laser is at least shorter than the time ittakes for the surface of the crystalline semiconductor particles 103 tosolidify after fusion, a fusion-bonding reaction of the crystallinesemiconductor particles 103 can be carried out continuously, andgeneration of a defect at an interface of fusion-bonding, which becomesa carrier trap, can be suppressed. Another CW laser or another pulsedlaser with a repetition frequency of 10 MHz or more can also be used.For example, as a gas laser, an Ar laser, a Kr laser, a CO₂ laser, orthe like is given. As a solid laser, a YAG laser, an YLF laser, YAlO₃laser, a GdVo₄ laser, a KGW laser, a KYW laser, an alexandrite laser, aTi:sapphire laser, a Y₂O₃ laser, a YVO₄ laser, or the like is given.Further, a YAG laser, a Y₂O₃ laser, a GdVO₄ laser, a YVO₄ laser, or thelike is given as a ceramic laser. As a metal vapor laser, a heliumcadmium laser or the like is given. Furthermore, an excimer laser ofpulsed oscillation may be used.

FIG. 4 shows a step of forming an n-type semiconductor layer 105 and asecond electrode 106 over the crystalline semiconductor particles 104that are fusion-bonded. The n-type semiconductor layer 105 is formed ofpolycrystalline silicon doped with phosphorus (P) or the like;microcrystalline silicon; amorphous silicon; or the like. The n-typesemiconductor layer 105 is formed to have a thickness of 10 nm to 100nm, and with this, a p-n junction is formed.

Over the n-type semiconductor layer 105, the second electrode 106 isformed. The second electrode 106 may be formed with a transparentconductive film made of indium oxide, indium tin oxide, zinc oxide, orthe like. Alternatively, the second electrode 106 may be formed as acomb-shaped metal electrode. In this manner, the photoelectricconversion device can be obtained.

In the photoelectric conversion device of this embodiment mode, movementof carriers generated in crystalline semiconductor particles 107 in alateral direction is not inhibited, and a significant effect is obtainedwhere there is not much difference compared to a case of forming thislayer from a single monocrystalline silicon layer. Also, in order toabsorb sunlight as a photoelectric conversion device, it is said that athickness of 10 micrometers is sufficient; however, according to thephotoelectric conversion device of this embodiment mode, crystallinesemiconductor particles each with a grain diameter of severalmicrometers to several tens of micrometers may be dispersed andfusion-bonded. Therefore, resource of silicon is not wastefullyconsumed.

Embodiment Mode 2

FIGS. 5 to 8 describe manufacturing steps of a photoelectric conversiondevice of this embodiment mode. In this embodiment mode, an example ofmanufacturing a photoelectric conversion device using finer crystallinesemiconductor particles each with a grain diameter of several nanometersto several tens of nanometers (1 nanometer to 99 nanometers), in orderto improve conversion efficiency, is described.

As shown in FIG. 5, the first electrode 102 is formed over the substrate101 in a similar manner to Embodiment Mode 1. Then, the crystallinesemiconductor particles 107 each with a grain diameter of severalnanometers to several tens of nanometers are densely dispersed andformed over the first electrode 102. The crystalline semiconductorparticles 107 are formed of silicon (Si), germanium (Ge) or the like,and the crystalline semiconductor particles 107 may contain boron (B) oraluminum (Al) which is p-type, or phosphorus (P) or arsenic (As) whichis n-type.

The crystalline semiconductor particles 107 can be formed by an aerosollaser ablation method, a pyrolysis method, or a vapor growth method.

FIG. 9 shows a structure of an aerosol laser ablation apparatus forgenerating crystalline semiconductor particles of this embodiment mode.The aerosol laser ablation method is a method of forming semiconductorparticles of several nanometers to several hundred nanometers (1nanometer to 999 nanometers) by transporting a raw material solutionthat is a solution in which semiconductor particles are dissolved ordispersed, aerosolizing the raw material solution by an atomizer, andthen irradiating the raw material solution with a laser beam. In thisembodiment mode, it is preferable to use crystalline semiconductorparticles, and as a semiconductor, silicon, germanium, silicongermanium, or the like can be applied.

As shown in FIG. 9, the aerosol laser ablation apparatus includes anaerosol generator 201 that generates aerosol from micron-sizecrystalline semiconductor particles; a neutralizer 202 that charges themicron-size crystalline semiconductor particles using radiation as wellas prevents the crystalline semiconductor particles from being adsorbedby an inner wall of a pipe when passing therethrough; a laser lightsource 206 that irradiates the aerosol with a laser beam; and anablation chamber 203 that generates nanoparticles by irradiatingmicron-size crystalline semiconductor particles flowing in from theaerosol generator 201 with a laser beam. As a carrier gas of thecrystalline semiconductor particles, helium gas, nitrogen gas, argongas, or the like can be used.

The laser beam is introduced from a laser beam introduction window 207that is provided for the ablation chamber 203. In order for the laserbeam to efficiently act on the crystalline semiconductor particles thatare aerosolized and supplied, the laser beam that has penetrated isreflected off a mirror 208 and is made to be introduced to the ablationchamber 203 again. As a laser light source, it is preferable to use anexcimer laser as an ultraviolet laser, and in addition, a high powersolid laser can also be used.

Nanoparticles of a crystalline semiconductor which are generated in theablation chamber 203 passes through a size sorter 204 that separatesparticles of several hundred nanometers or larger, by utilizingdifference in kinetic energy according to size of the nanoparticles.Semiconductor particles of several nanometers to several hundrednanometers that have passed thorough the size sorter 204 accumulate overthe substrate 101 placed in a sample chamber 205.

Also, FIG. 10 shows a chemical vapor growth (CVD) apparatus utilizingelectron cyclotron resonance (ECR), and semiconductor particles can alsobe generated by such an apparatus. In this apparatus, a cavity resonator209 is attached to a sample chamber 211. Coils 210 for direct-currentfield generation are attached to the cavity resonator 209. A waveguide213 is connected to the cavity resonator 209, and microwave is suppliedfrom a quartz window that transmits microwave. A raw material gas suchas silane or disilane is supplied by a gas supplying means 212 from oneend of the cavity resonator 209 that is away from the sample chamber211. The substrate 101 over which the semiconductor particles areaccumulated is supported by a stage 214 that is inside the samplechamber 211. The stage 214 can heat the substrate 101 to a temperatureof about 100° C. to 500° C.

The crystalline semiconductor particles are manufactured under acondition in which silane gas or silane gas and hydrogen gas aresupplied by the gas supplying means 212, and a reaction pressure is setat 0.1 to 0.05 Pa, a microwave power is set at 300 W to 1 kW, andstrength of a resonance magnetic field is set at 875 G. for example. Atthis time, a propagation direction of the microwave is lengthened in thecavity resonator 209, and the raw material gas is supplied into thecavity resonator 209 from one end that is away from the sample chamber211. Consequently, the raw material gas is broken up in the cavityresonator 209, and in a gas phase, crystalline semiconductor particlesof several nanometers to several tens of nanometers can be obtained by apolymerization reaction. By adding hydrogen to silane or disilane as theraw material gas, microcrystal grains can be obtained by a surfaceinactivation reaction of nanoparticles that are in a gas phase.

FIG. 6 shows a step of forming a crystalline semiconductor particlelayer 108 by fusion-bonding the crystalline semiconductor particles 107that have accumulated over the substrate 101. Further, a treatment bywhich the crystalline semiconductor particles 107 are fixed by heatingthe first electrode 102 through a heat treatment is also carried out. Byfusion-bonding the crystalline semiconductor particles 107 to eachother, an area for absorbing light increases within a substrate surface.The crystalline semiconductor particles 104 that are fusion-bonded allowdiffusion of photogenerated carries to an adjacent crystallinesemiconductor particle, and therefore efficiency of carrier collectionis improved. That is, since the area substantively contributing tophotoelectric conversion increases by this step, conversion efficiencycan be improved.

The crystalline semiconductor particles 107 that have beenmicroparticulated to several nanometers to several hundred nanometerseach have a large surface area, and may come to a state where theparticles are electrically fusion-bonded to each other. The subsequentstep may be carried out while in this state; however, it is morepreferable that a treatment of fusion-bonding by heat treatment orirradiation by a laser beam is carried out. The nanoparticlesfusion-bond at a lower temperature than an inherent melting point of amaterial thereof; therefore, they do not have an adverse affect withrespect to the first electrode 102 also. However, the treatment offusion-bonding the crystalline semiconductor particles 107 to each otheris preferably carried out by irradiation of a laser beam.

In a case of making a photoelectric conversion layer to be thicker withthe crystalline semiconductor particle layer 108 that is fusion-bonded,the crystalline semiconductor particles 107 are accumulated even more byan aerosol laser ablation method, a pyrolysis method, or a vapor growthmethod, and then a treatment of fusion-bonding the crsytallinesemiconductor particles is carried out. By repeating such a step, aphotoelectric conversion layer of a desired thickness can be formedusing the crsytalline semiconductor particle layer 108 that isfusion-bonded, as shown in FIG. 7.

FIG. 8 shows a step of forming the n-type semiconductor layer 105 andthe second electrode 106 over the crystalline semiconductor particlelayer 108 that is fusion-bonded. The n-type semiconductor layer 105 isformed of polycrystalline silicon, microcrystalline silicon, amorphoussilicon or the like doped with phosphor (P) or the like. The n-typesemiconductor layer 105 is formed to have a thickness of 10 nm to 100nm, and by this, a p-n junction is formed.

Over the n-type semiconductor layer 105, the second electrode 106 isformed. The second electrode 106 may be formed with a transparentconductor film made of indium oxide, indium tin oxide, zinc oxide, orthe like. Alternatively, the second electrode 106 may be formed as acomb-shaped metal electrode. In this manner, the photoelectricconversion device can be obtained.

In the photoelectric conversion device of this embodiment mode, movementof carriers in a lateral direction is not inhibited in the layer formedof the crystalline semiconductor particles 107, and a significant effectis obtained where there is not much difference compared to a case offorming this layer of a single monocrystalline silicon layer. Also, byforming a p-n junction by retaining a shape of the crystallinesemiconductor particles of several hundred nanometers, asperity of asurface becomes about the same as a wavelength of light absorbed by thesemiconductor, and reflection of incident light can be suppressed. Inother words, reflectance loss of light can be suppressed.

Embodiment Mode 3

In this embodiment mode, an intrinsic semiconductor is used forcrystalline semiconductor particles, and FIG. 11 shows a photoelectricconversion device in which a so-called pin junction is formed. Note thatthe intrinsic semiconductor mentioned here refers to a semiconductor inwhich a concentration of an impurity therein imparting p-type or n-typeis 1×10²⁰ cm⁻³ or lower, a concentration of oxygen and nitrogen are each9×10¹⁹ cm⁻³ or lower, and of which a photoconductivity is 1000 times adark conductivity or more. Further, 10 to 1000 ppm of boron (B) may beadded to this intrinsic semiconductor.

In FIG. 11, the first electrode 102 is formed over the substrate 101,and then a one-conductivity type semiconductor layer 109 is formedthereover. For example, a p-type semiconductor layer is formed by aplasma CVD method. The one-conductivity type semiconductor layer 109 maybe of a microcrystalline semiconductor. Then, crystalline semiconductorparticles 110 are formed as the intrinsic semiconductor thereover, in asimilar manner to Embodiment Mode 1 or 2. Although one-conductivity typecrystalline semiconductor particles are used in Embodiment Modes 1 and2, these may be replaced with intrinsic crystalline semiconductorparticles. In this case also, the intrinsic crystalline semiconductorparticles are formed so that at least adjacent particles arefusion-bonded to each other. Then, the n-type semiconductor layer 105and the second electrode 106 are formed thereover to obtain aphotoelectric conversion device.

Note that in this embodiment mode, although a metal electrode can beapplied as the first electrode 102, and a transparent electrode can beapplied as the second electrode 106, electrode forming materials may beinterchanged so that a structure may be that of allowing entrance oflight from the first electrode. By having a structure in which light isallowed entrance from a p-type semiconductor layer, diffusion length ofholes can be made to be short, and conversion efficiency can beimproved.

According to this embodiment mode, conversion efficiency can be improvedby forming a pin junction. Since crystalline semiconductor particlesthat play a central role in photoelectric conversion have crystallinestructures, lifetime of a minority carrier is long, and extractionefficiency of photogenerated carriers can be improved. Further, there isno problem of light deterioration, like how it becomes a problemparticularly when using amorphous silicon, and reliability can beimproved.

Note that this embodiment mode can be carried out in free combinationwith Embodiment Mode 1 or 2.

Since a junction region of the photoelectric conversion device shown inEmbodiment Mode 1 to 3 can be formed on a light-accepting surface,conversion efficiency is high because efficiency of carrier collectionis favorable. In particular, since a p-n junction is formed whileretaining a shape of the crystalline semiconductor particles, area oflight acceptance substantively contributing to photoelectric conversionis increased, which contributes to improving conversion efficiency.

Note that although in Embodiment Modes 1 and 2, the crystallinesemiconductor particles are p-type, and a step is described where ann-type semiconductor layer is formed after forming the crystallinesemiconductor particles, a combination may be reversed. In other words,the crystalline semiconductor particles may be n-type, and a p-typesemiconductor layer maybe formed thereafter.

Note that although in Embodiment Modes 1 and 2, a step is describedwhere a first electrode, crystalline semiconductor particles, asemiconductor layer, and a second electrode are formed in this order,the order may be changed. In other words, a first electrode, asemiconductor layer, crystalline semiconductor particles, and a secondelectrode may be formed in this order.

As described above, the modes of a photoelectric conversion device shownbelow can be derived according to the present invention.

A photoelectric conversion device includes one-conductivity typecrystalline semiconductor particles, of which adjacent particles arefusion-bonded to each other and of which a portion is in contact with afirst electrode; a semiconductor layer for forming a junction with theone-conductivity type crystalline semiconductor particles, that has anopposite conductivity type to the one-conductivity type; and a secondelectrode formed thereover.

A photoelectric conversion device includes a one-conductivity typecrystalline semiconductor particle layer, of which a portion is incontact with a first electrode, and is formed by stacking a plurality ofcrystalline semiconductor particles of which adjacent particles arefusion-bonded to each other; a semiconductor layer for forming ajunction with the one-conductivity type crystalline semiconductorparticle layer, that has an opposite conductivity type to theone-conductivity type; and a second electrode formed over thesemiconductor layer.

A photoelectric conversion device including a one-conductivity typesemiconductor layer formed over a first electrode; crystallinesemiconductor particles of which adjacent particles are fusion-bonded toeach other, formed over the one-conductivity type semiconductor layer; asemiconductor layer formed over the crystalline semiconductor particles,that has an opposite conductivity type to the one-conductivity type; anda second electrode formed over the semiconductor layer that has theopposite conductivity type to the one-conductivity type.

A manufacturing method of a photoelectric conversion device including astep of densely dispersing one-conductivity type crystallinesemiconductor particles over a first electrode; a step of heating thefirst electrode to fix the crystalline semiconductor particles to thefirst electrode; a step of fusion-bonding adjacent crystallinesemiconductor particles to each other; a step of forming a semiconductorlayer over the crystalline semiconductor particles that arefusion-bonded, that has an opposite conductivity type to theone-conductivity type; and a step of forming a second electrode over thesemiconductor layer that has the opposite conductivity type to theone-conductivity type.

A manufacturing method of a photoelectric conversion device including astep of densely dispersing one-conductivity type crystallinesemiconductor particles over a first electrode; a step of heating thefirst electrode to fix the crystalline semiconductor particles to thefirst electrode; a step of forming a crystalline semiconductor particlelayer by fusion-bonding adjacent crystalline semiconductor particles toeach other; a step of carrying out once or a plurality of times atreatment of dispersing and fusion-bonding crystalline semiconductorparticles over the crystalline semiconductor particle layer; a step offorming a semiconductor layer over the crystalline semiconductorparticle layer, that has an opposite conductivity type to theone-conductivity type; and a step of forming a second electrode over thesemiconductor layer that has the opposite conductivity type to theone-conductivity type.

A manufacturing method of a photoelectric conversion device including astep of forming a one-conductivity type semiconductor layer over a firstelectrode; a step of forming intrinsic crystalline semiconductorparticles over the one-conductivity type semiconductor layer; a step offusion-bonding the intrinsic crystalline semiconductor particles; a stepof forming a semiconductor layer over the crystalline semiconductorparticles that are fusion-bonded, that has an opposite conductivity typeto the one-conductivity type; and a step of forming a second electrodeover the semiconductor layer that has the opposite conductivity type tothe one-conductivity type.

As the modes of a photoelectric conversion device described above, thepresent invention applies not only a photoelectric conversion device,but also a circuit element included in an integrated circuit. Thepresent invention is a semiconductor device which includes at least afirst electrode, crystalline semiconductor particles of which adjacentparticles are fusion-bonded, a semiconductor layer, and a secondelectrode. The semiconductor device applies, for example, a diodeincluded in an integrated circuit.

This application is based on Japanese Patent Application serial no.2006-009945 filed in Japan Patent Office on Jan. 18, 2006, the entirecontents of which are hereby incorporated by reference.

1. A semiconductor device comprising: a first electrode, crystallinesemiconductor particles over the first electrode, a semiconductor layerover the crystalline semiconductor particles, and a second electrodeover the semiconductor layer, wherein: the crystalline semiconductorparticles of which adjacent particles are fusion-bonded, the crystallinesemiconductor particles have a first conductivity type, and thesemiconductor layer has a second conductivity type which is differentfrom the first conductivity type.
 2. The semiconductor device accordingto claim 1, wherein the first electrode includes a material selectedfrom the group consisting of aluminum, indium, tin, zinc and acombination thereof.
 3. The semiconductor device according to claim 1,wherein each of the crystalline semiconductor particles includessilicon, germanium, or silicon-germanium.
 4. The semiconductor deviceaccording to claim 1, wherein a grain diameter of each of thecrystalline semiconductor particles is 1 micrometer to 99 micrometers.5. The semiconductor device according to claim 1, wherein a graindiameter of each of the crystalline semiconductor particles is 1nanometer to 999 nanometers.
 6. The semiconductor device according toclaim 1, wherein the semiconductor layer includes polycrystallinesilicon, microcrystalline silicon, or amorphous silicon.
 7. Thesemiconductor device according to claim 1, wherein the second electrodeincludes indium oxide, indium tin oxide, or zinc oxide.
 8. Asemiconductor device comprising: a first electrode, crystallinesemiconductor particles over the first electrode, a semiconductor layerover the crystalline semiconductor particles, and a second electrodeover the semiconductor layer, wherein: the crystalline semiconductorparticles of which adjacent particles are fusion-bonded, and in which atleast two crystalline semiconductor particles are stacked, thecrystalline semiconductor particles have a first conductivity type, andthe semiconductor layer has a second conductivity type which isdifferent from the first conductivity type.
 9. The semiconductor deviceaccording to claim 8, wherein the first electrode includes a materialselected from the group consisting of aluminum, indium, tin, zinc and acombination thereof.
 10. The semiconductor device according to claim 8,wherein each of the crystalline semiconductor particles includessilicon, germanium, or silicon-germanium.
 11. The semiconductor deviceaccording to claim 8, wherein a grain diameter of each of thecrystalline semiconductor particles is 1 micrometer to 99 micrometers.12. The semiconductor device according to claim 8, wherein a graindiameter of each of the crystalline semiconductor particles is 1nanometer to 999 nanometers.
 13. The semiconductor device according toclaim 8, wherein the semiconductor layer includes polycrystallinesilicon, microcrystalline silicon, and amorphous silicon.
 14. Thesemiconductor device according to claim 8, wherein the second electrodeincludes indium oxide, indium tin oxide, or zinc oxide.
 15. Asemiconductor device comprising: a first electrode, a firstsemiconductor layer over the first electrode, crystalline semiconductorparticles over the first semiconductor layer, a second semiconductorlayer over the crystalline semiconductor particles, and a secondelectrode over the second semiconductor layer, wherein: the crystallinesemiconductor particles of which adjacent particles are fusion-bonded,the first semiconductor layer has a first conductivity type, and thesecond semiconductor layer has a second conductivity type which isdifferent from the first conductivity type.
 16. The semiconductor deviceaccording to claim 15, wherein the first electrode includes a materialselected from the group consisting of aluminum, indium, tin, zinc and acombination thereof.
 17. The semiconductor device according to claim 15,wherein each of the crystalline semiconductor particles includes ofsilicon, germanium, or silicon-germanium.
 18. The semiconductor deviceaccording to claim 15, wherein a grain diameter of each of thecrystalline semiconductor particles is 1 micrometer to 99 micrometers.19. The semiconductor device according to claim 15, wherein a graindiameter of each of the crystalline semiconductor particles is 1nanometer to 999 nanometers.
 20. The semiconductor device according toclaim 15, wherein the semiconductor layer includes polycrystallinesilicon, microcrystalline silicon, and amorphous silicon.
 21. Thesemiconductor device according to claim 15, wherein the second electrodeincludes indium oxide, indium tin oxide, or zinc oxide.
 22. Amanufacturing method of a semiconductor device comprising: forming afirst electrode, forming crystalline semiconductor particles over thefirst electrode, that have a first conductivity type, heating the firstelectrode to fix the crystalline semiconductor particles to the firstelectrode, fusion-bonding adjacent particles of the crystallinesemiconductor particles, forming a semiconductor layer over thecrystalline semiconductor particles, that has a second conductivity typewhich is different from the first conductivity type, and forming asecond electrode over the semiconductor layer.
 23. The manufacturingmethod of a semiconductor device according to claim 22, wherein the stepof the fusion-bonding adjacent particles of the crystallinesemiconductor particles is carried out after the step of heating thefirst electrode.
 24. The manufacturing method of a semiconductor deviceaccording to claim 22, wherein the step of fusion-bonding adjacentparticles of the crystalline semiconductor particles is carried out byheating.
 25. The manufacturing method of a semiconductor deviceaccording to claim 22, wherein the step of the fusion-bonding adjacentparticles of the crystalline semiconductor particles is carried out byirradiating with a laser beam.
 26. The manufacturing method of asemiconductor device according to claim 22, wherein the crystallinesemiconductor particles are formed by an aerosol laser ablation method,a pyrolysis method, or a vapor growth method.
 27. A manufacturing methodof a semiconductor device comprising: forming a first electrode, forminga first crystalline semiconductor particles over the first electrode,that have a first conductivity type, heating the first electrode to fixthe first crystalline semiconductor particles to the first electrode,fusion-bonding adjacent particles of the first crystalline semiconductorparticles, forming a second crystalline semiconductor particles over thefirst crystalline semiconductor particles, that have the firstconductivity type, fusion-bonding adjacent particles of the secondcrystalline semiconductor particles, forming a semiconductor layer overthe second crystalline semiconductor particle, that has a secondconductivity type which is different from the first conductivity type,and forming a second electrode over the semiconductor layer.
 28. Themanufacturing method of a semiconductor device according to claim 27,wherein the step of the fusion-bonding adjacent particles of the firstcrystalline semiconductor particles is carried out after the step of theheating the first electrode.
 29. The manufacturing method of asemiconductor device according to claim 27, wherein the step of thefusion-bonding adjacent particles of each of the first crystallinesemiconductor particles and the second crystalline semiconductorparticles is carried out by heating.
 30. The manufacturing method of asemiconductor device according to claim 27, wherein the step of thefusion-bonding adjacent particles of each of the first crystallinesemiconductor particles and the second crystalline semiconductorparticles is carried out by irradiating with a laser beam.
 31. Themanufacturing method of a semiconductor device according to claim 27,wherein the crystalline semiconductor particles are formed by an aerosollaser ablation method, a pyrolysis method, or a vapor growth method. 32.A manufacturing method of a semiconductor device comprising: forming afirst electrode, forming a first semiconductor layer over the firstelectrode, that has a first conductivity type, forming crystallinesemiconductor particles over the semiconductor layer, fusion-bonding thecrystalline semiconductor particles, forming a second semiconductorlayer over the crystalline semiconductor particles, that has a secondconductivity type which is different from the first conductivity type,and forming a second electrode over the second semiconductor layer. 33.The manufacturing method of a semiconductor device according to claim32, wherein the step of the fusion-bonding adjacent particles of thecrystalline semiconductor particles is carried out after the step of theheating the first electrode.
 34. The manufacturing method of asemiconductor device according to claim 32, wherein the step of thefusion-bonding adjacent particles of the crystalline semiconductorparticles is carried out by heating.
 35. The manufacturing method of asemiconductor device according to claim 32, wherein the step of thefusion-bonding adjacent particles of the crystalline semiconductorparticles is carried out by irradiating with a laser beam.
 36. Themanufacturing method of a semiconductor device according to claim 32,wherein the crystalline semiconductor particles are formed by an aerosollaser ablation method, a pyrolysis method, or a vapor growth method.